<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .demo {
            width: 500px;
            height: 250px;
            background-color: pink;
            margin: 10px auto;
            border-radius: 500px 500px 0 0;
        }
    </style>
</head>

<body>
    <div class="demo">

    </div>
</body>

</html>